Earlier on Sunday, Ten Eyewitness News understands Thai Navy SEAL divers and international divers held a briefing before authorities ordered an evacuation of the area around the Tham Luang cave complex.

Journalists & non-essential personnel are ordered to leave the cave site and surrounding roads as the rescue operation begins to evacuate the trapped soccer team. Image: Getty

"Assessing the situation now, it is necessary to evacuate the area for the rescue operation,” Mai Sai police commander Komsan Sa-ardluan said over a loudspeaker as a large media pool began packing up equipment.

“Those unrelated to the rescue operation, please evacuate the area immediately.”

The boys, aged between 11 and 16, went missing with their 25-year-old coach after soccer practice on June 23 as they set out to explore the cave complex in a forest park near the border with Myanmar.

With oxygen levels dropping, time had been running thin to teach the boys -- who are not strong swimmers -- to make a dive through dark, narrow passageways.

But the former governor said all stations were now ready.

“We have prepared everyone on land, road and evacuation too. We have prepared the helipad. There are more than 13 ambulances. Now the 13 (boys and coach) of them -- their health and their minds are ready and they are ready to go out," he said.

Thirteen medical teams have been stationed outside the cave -- one for each of the boys and their coach. Each team has its own helicopter and ambulance, along with at least one doctor, two nurses and a paramedic.

“I beg everyone outside to pray for them and support them," the governor said.

He said the boys' families have been briefed and are fully prepared. So far the only direct contact has been through handwritten notes from the boys -- and replies from their parents.

The letters were posted to the Thai Navy SEALS Facebook page.

The rescue operation comes after a former member of Thailand’s elite navy SEAL unit died during a dive on Thursday night -- a grim turn in what began two weeks ago as an outing to celebrate the birthday of one of the boys.

Rescue Operation Update From Dan Sutton

Up on the hill, where rescuers had been seeking alternative routes down into the cave, another accident occurred when a vehicle skidded off a dirt track, seriously injuring several people, authorities said.